1. Field of the Invention
This invention relates to a via-drilling system and, more particularly, this invention relates to a low-cost, high-throughput drilling system for micro-via arrays, wherein energy from a single high-energy laser beam is multiplexed into multiple sub-beams to provide a related finite number of patterning beamlines, each beamline being equipped with appropriate mask-projection optics, for simultaneously drilling a finite number of separate, high-quality, mask-controlled multiple-micro-via patterns into a substrate.
2. Description of Related Art
The desire for multi-hole patterns of ultra-miniature via holes which are precisely located and are of precise dimensions (micro-via patterns) is recognized in the fields of multi-layer integrated circuits, ink-jet print heads, aerosol generation and micro-filtering, as well as in other fields as those fields become more miniaturized. Miniaturization has far exceeded the capability of the metal drill bit, at least for high-precision via-drilling in hard substrates, because of bit breakage and bending which destroys the symmetry and precision of the via-hole. Laser drilling has become the art of choice for drilling micro-via patterns in hard substrates. However, laser drilling is quite costly, and prior art technologies typically produce via-holes with low aspect ratios (hole depth:hole diameter) of .ltoreq.1:1, or produce imprecise via-hole dimensions, and have exhibited low yields of acceptable micro-via patterns. This invention overcomes these problems by providing a high-throughput system that is capable of drilling high-quality patterns of high-aspect-ratio via-holes.